Lung cancer is the number one cancer killer for men and women in the USA. The ability to detect lung cancer at its early, curable stages will reduce the mortality and is thus an important clinical goal. Toward this goal, using genome-wide microarray-based comparative genomic hybridization analysis of primary lung tumors, we have identified a set of genetic signatures that can be detected in sputum and provided potential biomarkers for the early detection of lung cancer (Clin Cancer Res, 2007, 15 and AACR breaking News). We have also developed an in situ mini-chip consisting of a panel of probes for simultaneously measuring multiple genetic changes in a single test. However, the application of the potential genetic biomarkers and test in the clinical settings is limited by the probes that are labeled with organic dyes, because the conventional fluorochromes fade fast and show blurry signals, and thus reduce the sensitivity of the biomarkers in the detection of cancer cells. The newly developed quantum dots (QDs) feature intense and stable fluorescence, and provide a promising approach for effectively detecting molecular genetic targets. The objective of this R03 exploratory study is to develop a diagnostic test that can reliably detect genetic biomarkers using sputum for the early detection of lung cancer. We propose to 1) develop a nanogenetic test by incorporating the most optimum fluorescent QDs into the probes of the genetic signatures and integrating the nanoprobes into the in situ mini-chip, 2) determine diagnostic utility of the nanogenetic test for the early detection of lung cancer in sputum samples from 83 patients with stage I lung cancer and 83 cancer-free heavy smokers and 83 nonsmokers. At the conclusion of this study, we expect to develop a genetic approach for effectively detecting the biomarker panel in sputum that can be used for the early detection of lung cancer with high sensitivity. This exploratory R03 grant will set the stage for future large-scale cohort studies designed to validate its utility for adoption in routine clinical settings. Resources that will contribute towards our objective include a bank of well-characterized sputum samples with comprehensive clinical and cytopathologic database.